"Could I regenerate this knowledge if it were somehow deleted from my mind?"

Epistemologically, that's my biggest problem with religion-as-morality, along with using anything else that qualifies as "fiction" as a primary source of philosophy. One of my early heuristic tests to determine if a given religious individual is within reach of reason is to ask them how they think they'd be able to recreate their religion if they'd never received education/indoctrination in that religion (makes a nice lead-in to "do people who've never heard of your religion go to hell?" as well). The possibles will at least TRY to imply that gods are directly inferable from reality (though Intelligent Design is not a positive step, at least it shows they think reality is real); the lost causes give a supernatural solution ("Insert-God-Here wouldn't allow that to happen! Or if He did, He'd just make more holy books!").

If such a person's justification for morality is subjective and they just don't care that no part of it is even conceivably objective... what does that say for the relationship of any of their moral conclusions to reality?